Conventionally, in case of producing metallic materials by solidification molding of powders, mechanical alloying using ball mills was applied to obtain a powder having a sufficiently finely divided texture to thereby increase the strength of the resulting solidified product, and, furthermore, HIP processing was used to eliminate the pores therefrom. Thus, not only a conventional production method for obtaining a solidified body from a metallic powder required a large production system and a consumption of a vast production time and cost because many process steps were involved, but also it have a great difficulty in supplying a great amount of material at a time to carry out the batch process.
Although mass production is feasible if mechanical alloying and HIP processes are omitted, on the other hand, the resulting material have not only an insufficient strength because of a coarse texture, but also insufficient elongation and rigidity owing to the formation of large amount of coarse pores inside it.
Accordingly, mechanical alloying process and the HIP process subsequent thereto were regarded as indispensable means in the production of a solidification body of metallic powders. Hence, it had been thought difficult to realize a powder solidification body having a higher strength and still yet improved in elongation.
Moreover, in a steel material, regardless of whether it is a solidification body of a metallic powder or not, a high strength material having a TS of 590 MPa or higher had been produced by properly incorporating an additional element such as C, Si, Mn, Nb, Cu, Ni, etc., at a quantity of 0.22 mass % or more in Pcm, and then by applying quenching and tempering, or employing controlled rolling or controlled cooling. However, the steel materials obtained in this manner required the addition of various types of rare elements, and, hence, the resulting materials suffered problems as such that they were not suitable for recycled use, or required preheating in case of applying welding, or caused hardening at the portions which were thermally influenced during welding. Moreover, because it was difficult to obtain a uniform texture for the entire cross section, heterogeneous material distribution was found in the steel material.